To Pharrell News Today

>> from the beatles. >> she loves you yeah, yeah, yeah. >> to pharrell. ♪ happy ♪ >> he sang happy 56 times and was number one for ten weeks, but its not foolproof. if my mom sang shake it off it wouldnt make it to number one. >> no, were not saying thats the one secret ingredient thats going to make a number one hit. >> reporter: but we now know it unquestionably helps. ♪ shake it off, shake it off ♪ ♪ shake it off, shake it off ♪ >> nick watt, abc news, los angeles. ♪ shake it of...